Convert from stick to gnat's eye

Unit Definition (stick)
A stick, when used as a unit, is usually two inches, i.e. 5.08 cm (for the international inch). It was once used in the English tailoring business, but has since fallen out of use completely.

Unit Definition (gnat's eye)
The gnat's eye is an idiomatic "unit" of distance; it's common to hear that something is "as small as a gnat's eye". In fact, the eyes of typical gnats tend to have diameters similar in size to a hair's breadth: roughly 100-150 micrometers (0.10-0.15 millimeters).